According to Percival P. Cassidy :
On 08/05/05 10:09 am Chris Lewis tossed the following ingredients into
the ever-growing pot of cybersoup:

Note that switches have (at least) two ratings. Interrupt rating
and passthru.

Some switches may indeed have a 10A max _switch_ rating, but they're
still rated 15A (or 20A) continuous. The switching rating is based
on arc erosion.

Huh!? If you are switching a device or devices that pull 15A while
operating, it's extremely unlikely that it/they will pull less than that
at switch-on time. ISTM that the switching capacity should be higher
than the "running" capacity.

The continuous rating is based around how much current can go through
closed contacts without overheating.

This is radically different, and usually considerably _higher_ than
you can do thousands of "make/break" cycles with.

The fact that a switch has a switch rating of 10A, with a continous
current rating of 20A doesn't mean that it's deliberately designed
for a circuit where this will happen all the time.

Not at all.

It just means that you limit the stuff you switch by it to 10A, but
if you have a resistive short in the switched stuff that only passes
20A, the switch can safely pass the maximum current that the breaker
will let through.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.